ABSTRACT

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).

Nontechnical Description: Improving power conversion efficiency in a wide range of applications including consumer appliances, all-electric and hybrid-electric vehicles, and extraction and conversion in cost-effective renewable energy sources can save energy, significantly reducing costs, benefiting both the economy and environment. The potential material system for revolutionizing power electronics components is ultra-wide bandgap semiconductors, a class of semiconductors with large bandgap energy. Enhancing their performance relies on critical understanding of mechanisms to efficiently generate and control charge carriers and how these carriers interact within the materials. This project reveals and describes ?what really happens? at the scale of charge carriers and microstructures within these material systems, including the dopant-defect interaction and how these atomic scale features affect the electrical functionalities. This work is made possible by an innovative approach that integrates a three-dimensional atomic scale imaging tool, atom probe tomography with statistical and computational modeling on the atomic scale data, establishing a direct link with the electrical conductivity that would be difficult to identify and mitigate otherwise. The principal investigator strives to inspire students at undergraduate and graduate levels, especially women and underrepresented minorities, to pursue a career in materials science and engineering by exposing them to the exciting development of advanced materials to solve important societal problems. The principal investigator will also increase awareness of advanced material characterization to generate smart data for material design and development by organizing summer workshops and symposium. Coursework will emphasize multidisciplinary approaches to teach engineering concepts and connect them with real-world applications to solve challenges for the advancement of society.

Technical description: This research project will provide a fundamental understanding of electrical transport properties in ultra-wide band gap semiconductors to advance high power electronics and clean energy technologies. Ultra-wide bandgap semiconductor technology is hindered by the lack of knowledge of the dopant incorporation on electrical functionalities and identification and detection of atomic scale features contributing to charge compensation. A novel framework will be developed to detect and quantify dopant solubility, dopant diffusion, impurities, vacancies, and defect complexes by leveraging atom probe tomography coupled with machine learning and statistical modeling on microscopy data. The overarching goal is to generate know-how on the impact of microstructures on electrical transport, beyond the limits of existing techniques. This research aspires to transform the doping engineering and electrical conductivity optimization by: i) developing novel methodologies that can characterize dopant incorporation and dopant-defect interaction that leads to charge compensation with unprecedented resolution and precision; ii) gaining new insight into how atomic to nanoscale structures and defects impacts the electrical transport; iii) validating existing theories on charge compensation and providing important inputs for further developing material structure-chemistry for power electronics and clean energy generation, and iv) acquiring new knowledge on material structure and chemistry to aid the principles and design criteria to achieve outstanding material performance in ultra-wide bandgap semiconductors and beyond. The closely integrated research and education components provide interdisciplinary training opportunities for undergraduate and graduate students on advanced microscopy, machine learning modeling, and ultra-wide bandgap semiconductors.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

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